1. Field of the Invention
The present invention relates to illuminating apparatus and device manufacturing methods and, more particularly relates to an illuminating apparatus and a device manufacturing method suitable in processing a nozzle hole or a groove of an ink reservoir of an orifice plate for an ink-jet printer.
2. Description of the Related Art
Recently, it is increasingly common to fabricate a precision part by a mask projection method. Lasers are used as the light source and a pattern on a mask illuminated by a laser beam is projected by a projection lens onto a surface to be processed so that the precision processing is effected by an optical energy of the laser beam which has passed through the pattern. This method is particularly excellent in its high productivity and in that the processing may be effected stably at a high precision.
One of the types of part processing suitably using the mask projection method is the processing of an orifice plate for an ink-jet printer or a bubble jet printer (hereinafter referred to as an ink-jet printer). In general, an ink-jet printer refers to the type of printer in which characters or graphics are printed by intermittently ejecting ink onto a surface of a sheet from a large number of small holes having a diameter of 20 to 50 .mu.m which are arranged in a row. An orifice plate refers to a member having the large number of small holes (nozzles) for ejecting the ink. In order to improve the quality of characters to be printed, it is important, in addition to an accurate control of timing of the ink ejection, that the large number of small holes on the orifice plate be provided at a high precision. Further, in order to lower the cost per unit of the orifice plate, i.e., the cost per unit of printer, it is necessary to improve the productivity in mass production of the orifice plate. If the orifice plate is manufactured by using the mask projection method, it is important to efficiently illuminate the pattern of a mask.